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A Strong Jet Signature in the Late-time Light Curve of GW170817

Mooley, K. P. and Frail, D. A. and Dobie, D. and Lenc, E. and Corsi, A. and De, K. and Nayana, A. J. and Makhathini, S. and Heywood, I. and Murphy, T. and Kaplan, D. L. and Chandra, P. and Smirnov, O. and Nakar, E. and Hallinan, G. and Camilo, F. and Fender, R. and Goedhart, S. and Groot, P. and Kasliwal, M. M. and Kulkarni, S. R. and Woudt, P. A. (2018) A Strong Jet Signature in the Late-time Light Curve of GW170817. Astrophysical Journal Letters, 868 (1). Art. No. L11. ISSN 2041-8213.

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We present new 0.6–10 GHz observations of the binary neutron star merger GW170817 covering the period up to 300 days post-merger, taken with the upgraded Karl G. Jansky Very Large Array, the Australia Telescope Compact Array, the Giant Metrewave Radio Telescope and the MeerKAT telescope. We use these data to precisely characterize the decay phase of the late-time radio light curve. We find that the temporal decay is consistent with a power-law slope of t^(−2.2), and that the transition between the power-law rise and decay is relatively sharp. Such a slope cannot be produced by a quasi-isotropic (cocoon-dominated) outflow, but is instead the classic signature of a relativistic jet. This provides strong observational evidence that GW170817 produced a successful jet, and directly demonstrates the link between binary neutron star mergers and short-hard gamma-ray bursts. Using simple analytical arguments, we derive constraints on the geometry and the jet opening angle of GW170817. These results are consistent with those from our companion very long baseline interferometry paper, reporting superluminal motion in GW170817.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Mooley, K. P.0000-0002-2557-5180
Dobie, D.0000-0003-0699-7019
Lenc, E.0000-0002-9994-1593
Corsi, A.0000-0001-8104-3536
De, K.0000-0002-8989-0542
Murphy, T.0000-0002-2686-438X
Kaplan, D. L.0000-0001-6295-2881
Nakar, E.0000-0002-4534-7089
Hallinan, G.0000-0002-7083-4049
Camilo, F.0000-0002-1873-3718
Groot, P.0000-0002-4488-726X
Kasliwal, M. M.0000-0002-5619-4938
Kulkarni, S. R.0000-0001-5390-8563
Woudt, P. A.0000-0002-6896-1655
Alternate Title:A Strong Jet Signature in the Late-Time Lightcurve of GW170817
Additional Information:© 2018 The American Astronomical Society. Received 2018 August 30; revised 2018 October 17; accepted 2018 October 29; published 2018 November 16. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. We thank the staff of the GMRT that made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology. The authors thank the NRAO staff, especially Mark Claussen and Amy Mioduszewski, for scheduling the VLA observations. K.P.M. would like to thank Kenta Hotokezaka and Michael Zhang for help with emcee. We thank Varun Bhalerao for help with some of the uGMRT observation A.C. acknowledges support from the NSF CAREER award #1455090. D.D. is supported by an Australian Government Research Training Program Scholarship. K.P.M. is currently a Jansky Fellow of the National Radio Astronomy Observatory. T.M. acknowledges the support of the Australian Research Council through grant FT150100099. Part of this work was supported by the GROWTH (Global Relay of Observatories Watching Transients Happen) project funded by the National Science Foundation under PIRE grant No. 1545949. DK was additionally supported by by NSF grant AST-1412421. P.C. acknowledges support from the Department of Science and Technology via Swarana Jayanti Fellowship award (file no.DST/SJF/PSA-01/2014-15). The research of O.S. is supported by the South African Research Chairs Initiative of the Department of Science and Technology and NRF. Software: Matplotlib (Hunter 2007), NumPy (Oliphant 2006), MIRIAD (Sault et al. 1995), DIFMAP (Shepherd 1997), CASA (McMullin et al. 2007), emcee (Foreman-Mackey et al. 2013), corner (Foreman-Mackey 2016).
Group:Astronomy Department
Funding AgencyGrant Number
Commonwealth of AustraliaUNSPECIFIED
Australian GovernmentUNSPECIFIED
National Radio Astronomy ObservatoryUNSPECIFIED
Australian Research CouncilFT150100099
Department of Science and Technology (India)DST/SJF/PSA-01/2014-15
South African Research Chairs InitiativeUNSPECIFIED
Department of Science and Technology (South Africa)UNSPECIFIED
National Research Foundation (South Africa)UNSPECIFIED
Subject Keywords:gravitational waves – radio continuum: stars – stars: neutron
Issue or Number:1
Record Number:CaltechAUTHORS:20181120-111912911
Persistent URL:
Official Citation:K. P. Mooley et al 2018 ApJL 868 L11
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91071
Deposited By: Tony Diaz
Deposited On:20 Nov 2018 21:32
Last Modified:09 Mar 2020 13:18

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